The horde of people gathered on the streets outside Liverpool Street train station, one of the city's major transport hubs, and burst out into cheers, chants and dances to the tunes of "Billie Jean," "Bad" and "Thriller."

His messages went "viral" --spreading like wildfire around the Internet -- as the number of people wanting to join his impromptu "flash mob" event far exceeded his expectations:

"I don't know what I've unleashed here," Yiannopoulos, who said he doesn't even know how to moonwalk, told CNN.

He came up with the ideas "because of all of the stuff people are saying about Michael Jackson -- surgeries, molestation etc. -- I wanted to do something to remind people how great he really is and remind them of his music."

But those who were there did not seem to need much reminding of Jackson's greatness.

"He is the biggest idol in my life. Unfortunately, I did not grow up with all his best hits, but he has been so important for me. I am very sad," said 13-year-old Paul Graham, who wore a self-made Michael Jackson "Rest in Peace" T-shirt.